Power efficiency is one of the metrics of quality for substantially all electronic amplifiers, and has particular importance in certain applications. Examples of such applications include portable entertainment systems, particularly systems with audio speakers required to deliver high volume with low distortion. As well-known in the amplifier and acoustics arts, such requirements call for the speakers to produce significant sound pressure waves, i.e., rapidly displace large quantities of air, in a manner faithfully reproducing the original music. This requires high power amplifiers capable of pumping high average currents through the speaker drive coils, with adequate headroom to pump substantially higher peak currents, and capable of extremely fast change in value (i.e., a fast slew rate), with low distortion.
In mobile environments, both hand-portable and vehicular, power efficiency thus becomes a significant issue. More particularly, battery considerations and, of particular importance in automobiles, considerations of heat and of loading the vehicle's alternator become an issue. Also, in vehicle-installed systems, amplifiers are often mounted in a tightly packed manner such as, for example, behind automobile dashboards. Further, vehicle occupants often prefer the vehicle interior provide a high quality audio environment. This in turn often drives designs having a significant plurality of speakers such as, for example, a four speaker system (e.g., left front, right front, left rear and right rear), and even an eight speaker system, all of the speakers driven by a high power amplifier.
For these and other reasons, regardless of continuing progress in the audio system technologies, power efficiency and, therefore, heat remains an issue.
For these and other reasons, the present embodiments provide advancements in the art, having various described features, advantages, and benefits as well as others that will be apparent to persons of ordinary skill in the art upon reading this disclosure.